This invention relates to a mechanism for disconnecting electrical and/or fluid lines running between a host vehicle and a releasable vehicle.
Many types of spacecraft and missile systems utilize an umbilical extending between a host and a releasable vehicle. In a common example, a host carries the smaller vehicle until the vehicle is to be released and sent on its way to accomplish some particular mission. Before the host and the vehicle are mechanically separated, there is typically an electrical umbilical extending between the two, permitting electrical communication of information in both directions, and operational commands to be communicated from the host to the vehicle. There may also be a fluid (gas or liquid) umbilical that provides pressurization gas, cryogenic coolant, fuel, or other consumable material to the releasable vehicle from the host. When the releasable vehicle is mechanically separated from the host, the umbilicals must be disconnected.
Several types of mechanisms are now in use to accomplish umbilical disconnection. One common approach for disconnecting electrical umbilicals is to place a guillotine blade in a position to sever the umbilical. The blade is activated by a small explosive charge (termed a squib charge) that drives the blade through the electrical umbilical, severing it. Another approach is to provide a mechanical connector in the umbilical, and to use explosive bolts to separate the connector.
While existing umbilical release mechanisms work reliably and well in many applications, they suffer from drawbacks in others. The firing of even a small explosive charge near the vehicle to effect separation of the umbilical imparts a force to the vehicle from the expanding gases of the explosion, or may transmit a force to the vehicle by a jerk on the separating end of the umbilical. The applied force causes the vehicle's trajectory to change to a small degree. In some cases the small force exerted by the umbilical separation may be insignificant. However, if the host is, for example, a spacecraft operating in space or other vehicle, and the releasable vehicle is unpowered, has a small mass, or is powered with limited fuel, the force on the vehicle applied as a result of the umbilical separation, and the resulting trajectory change, may be unacceptable.
Existing umbilical disconnect approaches may also not meet other system requirements, such as weight or reliability limitations, or may be too costly. Also, it has been common practice to custom design each umbilical disconnect for a particular application. Since absolute reliability of operation is necessary, each custom disconnect must be extensively tested and qualified for its application. More versatility of the disconnect design is highly desirable, so that fewer designs must be qualified for operation.
There is therefore a need for an improved approach for reliably achieving umbilical release, which applies no force to the separating vehicle. The present invention fulfills this need, and further provides related advantages.